Method for treating maize seeds

ABSTRACT

A method for degerming maize is disclosed, wherein prior to decorticating and degerming step the maize is moistened and, optionally, heated.

Elite tates Mei 1 1 3,632,051

[72] Inventors Antonio Redo [52] US. Cl 241/8 Lanzago Di Silea, Italy; [51] Int. Cl B02c 3/04, Bruno Tognaua, Niederuzwil, Switzerland B02c 3/08, B02c 3/00 211 App]. No, 845,146 50 Field 61 Search 241/7-11 [22] Filed July 28, 1969 45 Patented Jan. 4, 1972 References Cited [73] Assignee Gebrueder Buehlel- AG UNITED STATES PATENTS Switzerland 707,058 8/1902 Gaff 241/8 Priority May 6,1966 1,972,666 9/1934 Pays 241/8 My 2,284,239 5/1942 Wagner 241/7 x [31] 10.468/68 2,347,215 4/1944 Pattee 241/8 Original application May 2, 1967, Ser. No. 635,592, [10W Patent N0. 3,476,326, dated Prlmary EmmmerDonald Kelly Nov. 4, 1969. Divided and this application and Town July 28, 1969, 861. N0. 845,146

ABSTRACT: A method for degerming maize is disclosed,

[54] METHOD FOR TREATING M AXZE SEEDS wherein prior to decorticating and degerming step the maize is 7 Claims 6 Drawing Figs moistened and, optionally, heated.

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SHEET 1 0F 2 INVENTORS ANTONIO RPabo BRUNO TObAlFhafi ATTORNEY mamcm 4m 3.632.051

SHEET 2 OF 2 INVENTORS ANTONIO Rana ammo roemazzn BY ma flu ATTORNEYS METHOD FOR TREATING MAIZE SEEDS This is a division of application Ser, No. 635,592, filed May 2, 1967, and now U.S. Pat. No. 3,476,326, issued Nov. 4, 1969.

This invention relates to a process for treating maize seeds.

In another known method, in which the degerming step is carried out in dry condition by impact, the maize seeds are broken, the germ is stripped and is subsequently separated by a densimetric table.

In this case, however, the perisperm membrane adheres, to a large extent, to the groats," thus giving rise to an increase of the fatty substance and fibers content of said groats."

An object of the present invention is to avoid the drawbacks enumerated above.

According to the present invention the method comprises the steps of pretreating the maize, by moistening for a period of less than 1 hour and, optionally, by heating, subjecting the pretreated maize seeds to a decorticating step so as to strip it of the perisperm membrane, and subsequently to a degerming step proper so as to separate the gem of the endosperm. Said pretreatment can take place, for example, by washing or soaking with or without the application of heat. The degerming step proper can be advantageously carried out, either with beating machines or by impact, or by one or more passes through a roll mill.

The decorticating step may be carried out in a machine comprising a casing which is at least partially perforated and a rotor carrying decorticating members and mounted for rotation within said casing, said rotor conveying the maize longitudinally from an inlet to an outlet. The decorticating members consist of polygonal discs which are concave towards the inlet side and convex towards the outlet side, the surface of said discs being formed, at least on the convex face, by planar zones arranged between straight lines connecting the apices of the discs with the axis of the rotor, the consecutive discs being mounted with an angular shift with respect to one another.

A significant advantage afforded by said shaping and arrangement of the decorticating members is that the maize seeds undergo a very gentle treatment. Owing to the particular constructional arrangement of the rotor the maize seeds, during their slow advance motion from the inlet side to the outlet side of the decorticating machine, are intermixed and subjected to a threefold decorticating action due to their mutual friction and to their friction against the disclike rotor members and the casing. The friction between the maize seeds and the casing is advantageously enhanced by providing a roughsurface area in the inner face of the casing. Preferably, the cylindrical casing of the machine is partitioned into three zones, one having an inner rough surface, another perforated, and the third smooth, the latter acting also as a lid. The major portion of the perisperm stripped from the seeds, admixed with a small amount of flour, germs and groats" is directly separated by causing it to pass through the perforated casing zone.

According to an advantageous embodiment of the decorticating machine, the outlet, is placed in a top portion of the header and, in order that the duration of the treatment may be adjusted, the free crosssectional area of the outlet can be appropriately varied.

The maize discharged from the machine is thoroughly decorticated and the subsequent stripping of the germ from the endosperm is greatly facilitated, thus making it possible to obtain, with a good yield, groats" with a low content of fatty substances, along with a germ with a high content of said fatty substances,

One form of decorticating machine for use in carrying out the decorticating step of the method according to the present invention will be more particularly described, merely by way of example and without any limitation, the description being aided by the accompanying diagrammatic drawings.

In the drawings:

FIG. 1 is a vertical longitudinal sectional view, taken along the line 1-1 of FIG. 2, of the decorticating machine.

FIG. 2 is a crosssectional view, taken along the line IIII of FIG. I.

FIG. 3 shows a portion of the machine rotor, only a few of the decorticating members being shown some in elevation and some partly sectioned.

FIG. 4 is a front view of the machine, as seen from the outlet side.

FIG. 5 is a vertical sectional view through the outlet, taken along the line VV of FIG. 4, and

FIG. 6 is a cross sectional view, similar to that of FIG. 2, showing an alternative embodiment of the machine.

Referring now to FIGS. 1 and 2, the fixed frame is formed by a cylindrical casing which is substantially divided into three portions: an internally rough portion 1, a perforated portion 2 and a smooth portion, forming a lid 3. The internal roughening of the portion 1 is obtained by providing ridges, but corrugations or other irregular surface patterns may be used.

At the header 4 (to the left as viewed in FIG. 1) there is an inlet 5 and, at the opposite header 6, an outlet 7 which is located at a level higher than that of the rotor axis, but may be at the same level.

In order that an adjustment, or variation, of the duration of the passes and of the treatment of the material through the machine may be achieved, a gate 8 is mounted in the outlet 7. Other appropriate members may be used for modifying the outlet crosssectional area instead of the gate 8 (FIG. 5). To cover the perforated portion 2 of the casing, a hopper 9 is connected, so as to collect and dump the perisperm membrane stripped from the seeds and those small quantities of flour, germ and groats which pass through the perforated portion 2 of the casing.

The machine headers rotatably support the rotor, which essentially comprises a plurality of decorticating members fastened to a shaft 10. Each member consist of a polygonal disc 11 which is concave towards the inlet side and convex towards the outlet side. In the example shown, said discs 11 are all quadrangular but they can have any other polygonal contour, such as a triangular outline.

It is possible to use, in the same machine, discs of different shapes. In the preferred embodiment the discs 11 have, on their convex side, a pyramidal shape, with substantially planar faces bounded by straight radial lines going from the disc corners to the center of the rotor axis. Similar shaping may be provided on the concave side. Consecutive discs of the rotor are angularly shifted with respect to one another, for example, according to a symmetrical pattern. The angular displacement in the form shown in 45. The direction of rotation of the rotor is such (see arrow in FIG. 2) that every point of its periphery passes, during the sequential rotation, in front of the rough surface portion 1, then in front of the perforated portion 2 and eventually in front of the smooth portion 3 of the casing.

Although the rotor shaft 10 in the form shown in FIGS. 1 to 5 is concentric with the cylindrical casing it can be eccentrically supported with respect thereto (see FIGv 6) and, positively displaced towards the perforated portion 2 of the cylindrical casing, a cleaning effect being thus provided for the perforated portion 2.

The operation of the machine is as follows:

The maize seeds, previously treated for a time of less than I hour, for example by moistening, are fed into the machine in a manner known per se through the inlet 5. The moving rotor slowly conveys the fed in seeds towards the outlet 7 due to the action of the convex side of the polygonal discs 11. The contrasting forces due to the rotor thrust and the braking action of the rough and the perforated portions of the casing give rise to a continuous friction between the maize seeds and the working surfaces and also between the maize seeds themselves, the desired gentle and effective decorticating action being thus simultaneously achieved. The perisperm membrane stripped from the seeds and that very small fraction of flour, germ and groats passing through the perforated portion 2 of the casing are collected in the hopper 9 and dumped therefrom for subsequent use or treatment.

The mass of decorticating seeds having still the germ attached thereto, comes out of the adjustable outlet 7 to undergo the subsequent degerming step proper, which can be carried out, for example, in an impact mill well known in the art or-by one or more passes through a mill roll.

Upon completion of degerming, the product is then passed to the apparatus for separating the groats from the germ, apparatus which is per se well known, such as a densimetric table, etc.

We claim:

1. The method for dry process treating maize seeds, comprising the steps of pretreating maize by moistening the maize seed for a period of less than 1 hour, subjecting the pretreated seed to a mechanical decorticating operation for stripping the perisperm membranes and subsequently to a degerming step proper so as to separate the germ from the endosperm.

2. A method according to claim 1, wherein the degerming operation is carried out by causing the decorticated seeds to pass one or more times through a roll mill.

3. The method according to claim 1, characterized therein by applying heat during the moistening of the maize seed.

4. The method according to claim 1, wherein the degerming step is carried out by subjecting the decorticated seed to a beating action.

5. The method according to claim 1, wherein the degerming step is carried out by subjecting the decorticate seed to an impacting action.

6. The method according to claim 1, characterized therein that the mechanical decorticating operation comprises charging the maize seed into one end of an enclosed axially extending space and removing it from the opposite end of the space, feeding the seed axially through the enclosed space by rotating it about the axis while directing it to the opposite end of the space, and providing a varying frictional action between the periphery of the enclosed space and the adjacent maize seed.

7. The method according to claim 6, wherein the step of providing varying frictional action comprises in series, as the maize seed rotates about the periphery of the enclosed space. providing a relatively roughened surface, a perforated surface and a smooth surface so that the varying frictional action is provided between the peripheral surface and the adjacent maize seeds and between the maize seeds inwardly from the peripheral surface. 

2. A method according to claim 1, wherein the degerming operation is carried out by causing the decorticated seeds to pass one or more times through a roll mill.
 3. The method according to claim 1, characterized therein by applying heat during the moistening of the maize seed.
 4. The method according to claim 1, wherein the degerming step is carried out by subjecting the decorticated seed to a beating action.
 5. The method according to claim 1, wherein the degerming step is carried out by subjecting the decorticate seed to an impacting action.
 6. The method according to claim 1, characterized therein that the mechanical decorticating operation comprises charging the maize seed into one end of an enclosed axially extending space and removing it from the opposite end of the space, feeding the seed axially through the enclosed space by rotating it about the axis while directing it to the opposite end of the space, and providing a varying frictional action between the periphery of the enclosed space and the adjacent maize seed.
 7. The method according to claim 6, wherein the step of providing varying frictional action comprises in series, as the maize seed rotates about the periphery of the enclosed space, providing a relatively roughened surface, a perforated surface and a smooth surface so that the varying frictional action is provided between the peripheral surface and the adjacent maize seeds and between the maize seeds inwardly from the peripheral surface. 